The invention relates to a method of injecting fuel for an internal combustion engine with high pressure fuel injection, with a high pressure pump having a cylinder with a pumping chamber delineated by a piston, and a control line which extends between the pumping chamber and a low pressure induction line and includes a magnetic valve, and a high pressure line which extends between the pumping chamber and at least one fuel injection nozzle and which includes a magnetic check valve, wherein the beginning and the end of the fuel injection is initiated by opening and closing of the magnetic valve.
The ATZ/MTZ special issue Motor und Umwelt '92, pages 28 ff. presents, on page 28, an article entitled "Electronic Controlled Fuel Injection for Clean Diesel Engine" by Toshihiko Amori, wherein an arrangement with a magnetic valve-controlled high pressure pump is described which, after closing the passage supplying fuel to the pumping chamber, feeds fuel via a high pressure line including a check valve to a common rail supply conduit from which fuel is supplied to all the injection nozzles.
By way of an electromagnetic valve arranged in a return line extending between the high pressure line and a low pressure line the fuel supply is controlled in dependence on the fuel supply requirements.
It is known from DE 21 07 266 C 2 to terminate the pressurized fuel supply to a common rail supply conduit depending on the demand for fuel; but this is achieved by a high pressure pump with inclined edge control of the termination of the compression stroke of the pump by which excess fuel is discharged into a conduit leading to a fuel storage. This procedure however results in a sudden fuel release with a rapid pressure collapse in the pump compression space.
It is further known from DE 34 36 768 C2 to control fuel supply depending on the requirements by means of a magnetic valve arranged in the low pressure fuel line, but with this arrangement, a controllable fuel pressure level should always be present for any injection procedure at the start of injection.
It is the object of the invention to provide a method of injection fuel with high fuel pressures by which pressure pulses which normally occur in the low-pressure fuel circuit when communication with the low pressure fuel circuit is re-established at the end of each compression stroke of the fuel pressurizing pump are avoided.